The present invention generally relates to an isolated gene fragment that encodes for acetate kinase, which confers disease resistance in plants. The gene can be cloned into an expression vector to produce a recombinant DNA expression system suitable for insertion into cells to create a transgenic plant containing the gene fragment. The present invention also relates to a method for conferring disease resistance in plants that consists of growing plant host cells transformed with the expression system and expressing the gene to impart such resistance to host cells. More particularly, the present invention relates to the introduction of bacterial acetate kinase (ack) into plants to induce systemic acquired resistance; a chimeric gene construct containing the ack sequence; an expression vector containing the chimeric gene construct; a plant cell transformed with the chimeric gene construct; a plant tissue transformed with the chimeric gene construct; and a transgenic plant transformed with the chimeric gene construct.
Pathogen defense in plants is a varied and complicated process, involving a host of local and systemic events geared towards arresting growth of a pathogen. The cascade of events that lead to pathogen resistance is usually triggered by recognition of any of a range of pathogen-produced molecules (or elicitors (1-3)), and involves rapid local responses (such as ion fluxes and production of reactive oxygen species at the site of ingress (4-6)) and more prolonged local and systemic events (localized cell death, production of poorly understood translocated messengers, and induction of the expression of genes whose products act to limit the spread of pathogens (7,8). These recognition events are often mediated by specific pairs of moleculesxe2x80x94pathogen-derived elicitors and cognate plant-encoded receptors (9-15). These receptors, when xe2x80x9cactivatedxe2x80x9d by their respective ligands, trigger a large number of subsequent events that are themselves mediated by a number of signaling pathways.
Interestingly, plants undergo similar responses when challenged by pathogenic organisms and by organisms that do not cause disease. Thus, in both instances, systemic induction of so-called defense genes occurs. However, in the case where resistance is to be manifest, a rapid response is apparent and can include localized cell death referred to as the hypersensitive response (HR), while a slower response occurs in cases where disease is the ultimate result. These observations serve to emphasize the fact that the timing of a response is an important factor in disease resistance in plants (16,17). Thus, while much is known about the signaling events involving early (local) and late (systemic) responses to pathogens, much remains to be learned regarding the multiplicity of signaling pathways and the integration of multiple pathways.
The present invention is the introduction of a gene encoding acetate kinase into plant cells and plants to increase their resistance to bacterial and fungal pathogens.
The invention provides novel chimeric gene constructs that contain an ack coding sequence.
The invention also provides transformed plant cells and transgenic plants transformed with novel chimeric gene constructs that contain the ack coding sequence.
The invention thus provides a method for the expression of the ack gene in the cytoplasm of plant cells and plants.
Additional advantages of the present invention will be set forth in the description and examples that follow, or may be learned from practicing the invention. These and other advantages may be realized and attained by means of the features, instrumentalities and/or combinations particularly described herein. It is also to be understood that the foregoing general description and the following detailed description are only exemplary and explanatory and are not to be viewed as limiting or restricting the invention as claimed.
The invention itself, together with further advantages, will best be understood by reference to the following detailed description, taken in conjunction with the accompanying drawings.